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In article <1eckcsINNb78@uwm.edu>, ballen@convex.csd.uwm.edu (Bruce Allen) 
writes:
> The title says it all:
> "How does a clamp-on ammeter work?"
> I'm thinking about one of the gadgets used to measure the 
> current in an automobile charging circuit, for instance.
> It has a pair of thick "jaws" that encircle the lead in 
> question, and a meter that reads out the current passing 
> through the encircled region, without intrusively breaking
> or touching the wire.  Does it sense the B field?  If so, how?
> 	Thanks,
> 		B. Allen
> 
> Please reply to ballen@dirac.phys.uwm.edu



	I understand how the AC clamp-on ammeters (eg. Amprobe) work,
but could someone explain how some models can measure DC current as well.
This puzzles me, since the ammeter is basically a clamp-on transformer, with
the clamp being the core.  If the current in the wire under test doesn't 
alternate, the transformer won't work.  Am I missing something obvious here?


	Any takers?  Thanks for the info!


Ken